VESTA – Ignition Insights

THE UK Health & Safety Laboratory conducted research [HSL0609] into ‘Unidentified Ignition Sources of Unplanned Flammable Releases‘ and found that ” … following investigations into major accidents that had a release and an ignition, about 60% of those incidents did not have an ignition source identified by the investigation” – so if you don’t know what caused it, how can you prevent it from happening (again) ?

BS EN 1127-1 “Explosive atmospheres – explosion prevention and protection. Basic concepts and methodology” lists 13 possible sources of ignition – many familiar, some less common (but credible).

We’ve visualised these sources on our Ignition Sources cards to help increase the awareness of all stakeholders (inc Employees, Contractors, Suppliers & Visitors):

Click for Ignition Source Cards

Cards can be attached to Hot Work Permits to remind personnel of the potential ignition sources they may encounter while carrying out the identified & assessed work. They can also be used to tag/label locations where known ignition sources exist.

Regulations associated with flammable/explosive atmospheres (gases, mists, or dusts) require risk assessments to be conducted and regularly reviewed – particularly if there is a reason to suspect that the risk assessment is no longer valid or there has been a significant change.

Like many analyses (PHA, DHA, LOPA, FMEA etc) these risk assessments are often carried out by consultants/contractors and may be done for, rather than with, frontline personnel. Conventional worksheet or tabular outputs may lie dormant until the next scheduled review, a major change, or an incident. These may be difficult to operationalise and have limited potential for ongoing assurance of the control of flammable atmospheres and ignition sources.

Bowties offer a clear, consistent, concise representation of the uncontrolled ignition of flammable atmospheres by a competent ignitor (i.e. one with sufficient energy) and the associated effects on people & assets.

VESTA (Visualising Explosive atmosphere Scenarios & Tracking barrier Assurance) – named after the Roman Goddess of the hearth (fireplace) – is the application of CGE Risk BowTieXP to evaluate & communicate primary ignition threats and their potential consequences – which may include secondary ignition (represented by bowtie chaining & relationship diagrams) of flammable atmospheres in connected systems.

The aim of the Integrity Cards portfolio is to use cards to increase awareness and bowties to improve understanding – we believe an improved understanding of uncontrolled ignition by visualising scenarios can improve the recognition and respect of the Human & Hardware barriers that prevent the threats or mitigate the consequences.

Ignition Source cards help RECOGNISE THREATS – don’t ignore or underestimate unfamiliar energy sources.

VESTA bowties help RESPECT BARRIERS – controls rarely improve with age, therefore your risk is changing (increasing) as barriers degrade or are defeated. Discuss these scenarios in your Operations/Maintenance/Management meetings.

“… when flammable vapour and air are mixed in the flammable range, experience shows that a source of ignition is liable to turn up, even though we have done everything possible to remove known sources of ignition. The only real effective way of preventing an ignition is to prevent leaks of flammable vapour

Trevor Kletz: ‘Learning from Accidents’

i.e. proper Containment/Control of flammable atmospheres means ignition cannot occur even if/when there is a capable source.

Have a look at the latest AIChE – American Institute of Chemical Engineers CCPS Beacon “Hot Work is more than Welding, Burning & Grinding“.

For more information on Ignition Source Cards & Bowties, please contact us.

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